Derivative Instruments and Hedging Activities (Details 1) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
Mar. 31, 2013	Dec. 31, 2012
Balance Sheet offsetting disclosure
Gross amount of recognized assets	$ 21
Gross amount offset in the statement of financial position, Derivative assets
Net amount of assets presented in the statement of financial position	21
Gross Amounts Not Offset in the Statement of Financial Position, Financial Instruments	21
Gross amounts not offset in the statement of financial position, Cash Collateral Received
Derivative assets, Net amount
Gross amount of recognized liabilities	106	353
Gross amount offset in the statement of financial position, Derivative liabilities
Net amount of liabilities presented in the statement of financial position	106	353
Gross amounts not offset in the statement of financial position, Financial Instruments	106	353
Gross Amounts Not Offset in the Statement of Financial Position, Cash Collateral Received
Derivative liabilities, Net amount

Derivative fair value of derivative asset amount not offset against collateral cash collateral received.

No definition available.

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- Definition

Derivative fair value of derivative liabilities amount not offset against collateral cash collateral received.

+ References

No definition available.

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- Definition

Fair value of the gross assets less the gross liabilities of a derivative asset or group of derivative assets.

+ References

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Fair values as of the balance sheet date of all assets resulting from contracts that meet the criteria of being accounted for as derivative instruments, net of the effects of master netting arrangements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

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Fair value of derivative asset, presented on a gross basis even when the derivative instrument is subject to master netting arrangements and qualifies for net presentation in the statement of financial position.

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The amount as of the balance sheet date of the fair value of derivative assets that in accordance with the entity's accounting policy was not offset against an obligation to return cash collateral under a master netting arrangement.

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The amount as of the balance sheet date of the fair value of derivative assets that in accordance with the entity's accounting policy was offset against an obligation to return cash collateral under a master netting arrangement.

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Fair value of derivative liability, presented on a gross basis even when the derivative instrument is subject to master netting arrangements and qualifies for net presentation in the statement of financial position.

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The amount as of the balance sheet date of the fair value of derivative liabilities that in accordance with the entity's accounting policy was not offset against the right to reclaim cash collateral under a master netting arrangement.

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The amount as of the balance sheet date of the fair value of derivative liabilities that in accordance with the entity's accounting policy were offset against the right to reclaim cash collateral under a master netting arrangement.

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Fair values as of the balance sheet date of all liabilities resulting from contracts that meet the criteria of being accounted for as derivative instruments, net of the effects of master netting arrangements.

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Fair value of the gross liabilities less the gross assets of a derivative liability or group of derivative liabilities.

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